API 601

This standard is a purchase specification for metallic, flat, ring-shaped gaskets for use in circular, raised-face, flanged pipe joints as described in ANSI B16.5, API 605, and MSS SP-44. Two types of gaskets are covered: double-jacketed corrugated gaskets and spiral-wound gaskets. Nominal sizes correspond to the nominal pipe sizes (NPS) in ASME B36.10M and to the pipe outside diameter (OD), in inches, when NPS is beyond the scope of ASME B36.10M. Certain sizes of these gaskets cannot be used with all flange types or flange bores.